My objective is to understand the central nervous system control of eye movements, by starting at the periphery and working back into the central nervous system. I shall attempt to determine how information about movement is coded by single neurons at various levels within the central nervous system. The first part of the project will examine the correlation between a heterogeneous population of extraocular muscle fibers and a heterogeneous population of motoneuron types. The second part of the project will identify the sources of inputs to the motoneurons and the function of each input in the production of eye movements. Techniques to be employed in this project include: electrophysiological recordings from single cells, study of muscle fiber structure after lesions in specific parts of the motor nucleus, and tracing of pathways, through the retrograde transport of horseradish peroxidase.